Mass production of free-standing gallium nitride crystals (free-standing substrates of gallium nitride crystals) using a hydride vapor phase epitaxy (HVPE) method has begun in around 2003. Owing to the mass production of free-standing gallium nitride crystals, BluRay has been put into practical use.
Conventionally, a gallium monochloride-ammonia system (GaCl—NH3 system) has been used as a reaction system in HVPE gallium nitride (GaN) crystal growth.
For example, WO 2008/038632 discloses that a GaN crystal is produced by the reaction of GaCl and NH3. Further, Japanese Patent Application Laid-Open (JP-A) No. 2006-14351 discloses producing GaN excessively doped with Si by the reaction of GaCl and NH3 in the presence of SiH2Cl2. Further, JP-A No. 11-354844 discloses a method of producing GaN by the reaction of NH3 and GaCl produced by the reaction of Ga and GaCl3.
Further, Journal of Crystal Growth 268 (2004) p. 475-477 (“Growth of GaN films by chloride vapour phase epitaxy”, E. Varadarajan et. al) reports growth of GaN using GaCl3 as a raw material.